It's still technically possible to limit global
warming to below 1.5C this century, according to new research
published in Nature Climate Change.
Only a small window of opportunity remains open, the
study says - and it is closing rapidly. Global carbon pricing or
its equivalent should have been implemented already and must
certainly be in place by 2020. The world would then need to become
carbon neutral by mid-century.
The new study pitches into a live and vociferous
debate over whether the world should be aiming to limit warming to
1.5C or 2C, and whether either target remains achievable. Carbon
Brief puts the new study's findings in context.
Limiting warming to 1.5C
So far, the globally agreed target for avoiding
dangerous climate change is to limit warming to
no more than 2C above pre-industrial levels. But more than
half of the world's nations represented under the UN's Framework
Convention on Climate Change (UNFCCC) are in favour of a tougher
1.5C target. These include the least developed and most vulnerable
countries, such as the small island states that are already
losing farmland to rising sea levels.
UNFCCC review process is underway to try to decide if a
1.5C goal would be more appropriate. Its initial
findings include that the impacts of even 1.5C of warming
would be "significant" and that a 1.5C limit would be "preferable"
to 2C. However, it warns that the science on the impacts of 1.5C
compared to 2C is "less robust" and that until new results become
available, any decision on strengthening the current 2C goal may
need to wait.
Today's new research aims directly into this relative
scientific void. It says: "So far, only a few studies have reported
scenarios consistent with a 1.5C limit… Here we fill this gap".
To find out if 1.5C remains possible it uses two "
integrated assessment models" that represent the world's energy
system and economy under different assumptions about the future of
global policy, development and growth.